This study investigated the effectiveness of a two-week programme of parent education and a sensory diet to reduce signs of fussiness in infants identified with Regulatory Sensory Processing Disorder (RSPD). The sensory diet was viewed as a complementary programme and was based on the Sensory Integration theory of Jean Ayers. The sample consisted of twelve infants who met the diagnostic criteria for RSPD. Data were gathered using the Infant Toddler Symptom Checklist and a parent interview. Infants were divided into two combined age bands as prescribed for the administration of the Infant Toddler Symptom Checklist. One group fell into the age band of 7-12 months of age and the other into the 13-24 months age band. Pre and post intervention measures allowed for comparison of data to determine the effect of the programme. Findings for this sample indicated a significant reduction in signs of fussiness in both groups (p<0.00), with a greater change evident in the 7-12 month group. The most significant changes were seen in self-regulatory and attachment behaviours. Difficulties with tactile, vestibular and auditory sensitivities related to sensory processing persisted indicating the need for further sensory integrative therapy. Parents reported a lack of knowledge and recognition of Regulatory Sensory Processing Disorder in infants by health professionals and as a result, there had been no referral to occupational therapists for sensory integration therapy in this sample group. Despite the small sample size, the results contribute to the emerging understanding of the influence of sensory modulation on dysfunctional infant behaviour.